Contemporary Applications of Transanal Endoscopic Microsurgery: Technical Innovations and Limitations

A novel step-by-step training program for transanal endoscopic surgery

BACKGROUND

The objective of our study is to develop an effective training platform for transanal endoscopic surgery and to validate a step-by-step training program for learning the basic skills necessary for this approach.

METHODS

We have designed a two-part study: an experimental study (with the aim to design the training platform and the training exercises - on synthetic and biological material) and a prospective analytical study, in order to validate the training program by enrolling as participants general surgery residents and specialists, without previous experience in transanal endoscopic interventions. The performance of the participants was assessed based on the time of completion, as well as the quality of the execution.

RESULTS

We have developed three different diameter platforms (5 cm, 7.5 and 10 cm), that can be used with both the TEO and TAMIS platforms; specific exercises were developed to train different surgical skills like manipulation of tissue, cutting, dissection and suturing. Forty participants were enrolled for the validation of the proposed training program (12 young residents, 16 senior residents and 12 specialist surgeons). A statistically significant improvement of the performance time, from round to round, was observed for all participants in all exercises. The time of completion for the exercises, considering the correct technical execution, was the shortest for more experienced surgeons: specialist surgeons, followed by senior residents and young residents. The biological material exercises, that closely recreate intraoperative conditions and had more strict technical requirements, were difficult to be performed by young residents; better completion rates were seen in senior residents, while all the participants in the specialist surgeons group have completed these exercises.

CONCLUSIONS

Our training program is an effective simulation based educational model for recreating intraoperative conditions particular to transanal endoscopic surgery. The proposed step-by-step training program has demonstrated to be useful in developing the important basic skills needed for transanal endoscopic surgery and assured the progress of all the participants, regardless of their surgical experience.

Non-conventional applications for Transanal endoscopic microsurgery. A single centre experience and a systematic review of literature

BACKGROUND

Transanal endoscopic microsurgery (TEM) and Transanal endoscopic operation (TEO) have been initially described for local excision of rectal adenomas and selected cases of rectal carcinomas. In the past decade, however, several new indications raised, and others could raise in the future. The aim of this review was to evaluate, both in the literature and in our personal experience, the use of TEM and TEO for nonconventional applications, different from rectal tumors.

METHODS

We conducted a systematic review of published papers and we selected articles reporting patients who underwent endoscopic surgery for other medical reason than polyp cancer resection, with TEM or TEO. PubMed, MEDLINE, EMBASE and bibliographies of the selected studies were searched for articles in English published up to May 2020 to identify all relevant articles. We excluded articles reporting TEM and TEO used for classical indications. We finally report our experience of non-conventional use of TEO in 5 patients with different diseases.

RESULTS

The research revealed 800 papers and among them we selected 52 articles for a total of 697 patients. Of all patients, only 52 had intraoperative or postoperative complications, with only 10 patients requiring major surgery.

CONCLUSIONS

Our study suggest that TEM and TEO may be valid alternatives to traditional surgery in situations other than its classical indication. These findings can positively impact on the care of patients, who could benefit from less invasive surgical procedures associated with lower morbidity.

A reproducible ex vivo model for transanal minimally invasive surgery

The authors conclude that transanal laparoendoscopic procedures to excise rectal tumors can be successfully reproduced in an ex vivo porcine anorectal model.

Background:

Rectal tumors can be excised through a number of minimally invasive transanal techniques including transanal excision, transanal endoscopic microsurgery, and transanal minimally invasive surgery (TAMIS). Specialty training is often required to master the nuances of these approaches. This study aimed to create a reproducible transanal excision training model that is suited for laparoendoscopic techniques.

Methods:

Frozen porcine rectum and anus with intact perianal skin were commercially obtained. Thawed specimens were then cut to approximately 20 cm in length. The proximal end of the rectum was then everted and suction applied to the mucosa to create pseudopolyps of various sizes (sessile and pedunculated). Larger pedunculated lesions were made by tying the base of the pseudopolyps with 5–0 monofilament sutures to gather more tissue. Methylene blue dye was injected submucosally into the lesions to simulate tattoos. The proximal rectum was then closed with sutures. The model was suspended in a trainer box by clamping the distal end in a ringed clamp and the proximal end to the box. Transanal excisions using TAMIS were then performed. The procedures were done by trained community colorectal surgeons attending courses on transanal minimally invasive surgery.

Results:

Both partial- and full-thickness excisions of sessile and pedunculated rectal lesions were successfully performed during simulated TAMIS by trained community surgeons learning this laparoendoscopic technique.

Conclusion:

Transanal laparoendoscopic procedures to excise rectal tumors can be successfully and reproducibly performed in an ex vivo porcine anorectal model.

Repeated transanal endoscopic microsurgery is feasible and safe

BACKGROUND

The benefits of transanal endoscopic microsurgery (TEM) for the excision of benign and low-grade malignant lesions in the low and middle rectum are well recognized. This study examined the feasibility and safety of a repeated TEM procedure.

PATIENTS AND METHODS

Patients who underwent a repeat TEM for excision of rectal lesions, either for involved resection margins or for local recurrence, between the years 2000 and 2010, were identified. Rectal lesion characteristics were retrieved. Mean operative times, length of hospital stay, and intra- and postoperative complications were compared between primary and repeated procedures. The postoperative histopathology reports were reviewed, and the adequacy of resection was determined. All patients completed a questionnaire based on the Wexner score for anal sphincter function evaluation.

RESULTS

Fourteen patients (3 female, 11 male) underwent a repeat TEM operation during the study period. All procedures were completed endoscopically. Indications for repeated TEM were involved margins in 12 patients and recurrence of benign tumor in 2. Mean operative time, mean length of hospital stay, and rate of postoperative complications were similar for primary and repeated TEM procedures (62.5 ± 17 versus 55 ± 23 minutes, P=.181; 1.7 ± 1.3 versus 1.7 ± 1.12 days, P=.99; and 35.7% versus 21.4%, P=.66, respectively). The Wexner score was comparable at baseline and after the first and the second TEM procedures (1.5 ± 2.3, 1.5 ± 2.3, and 3.3 ± 3.1, respectively; P=.188). No cases of fecal incontinence following a repeat TEM were documented.

CONCLUSIONS

Repeated TEM is feasible and safe and may be appropriate for selected patients.

Transanal endoscopic microsurgery for the resection of submucosal and retrorectal tumors

BACKGROUND

Transanal endoscopic microsurgery (TEM) was originally designed for local endoscopic excision of benign and low-grade mucosal rectal lesions through an endoscopic system. The procedure is particularly challenging for submucosal and retrorectal lesions, as the tumor margins are not well defined.

OBJECTIVE

To investigate patient and surgical characteristics of TEM as a treatment for submucosal rectal and retrorectal lesions.

METHODS

All the patients in our department of general surgery who underwent TEM for a submucosal rectal or retrorectal lesion, between the years 2001 and 2011, were identified. Their charts were reviewed and data pertaining to demographic characteristics and medical history, including tumor characteristics, were collected. Operative notes and histopathology reports were also reviewed. The adequacy of the tumor resection, that ism attainment of free margins, endoscopic completion of the procedure, and perioperative complications, were assessed.

RESULTS

Fifteen patients (5 females, 10 males), mean age 53.9 ± 16.9 years, were identified. The main indications for surgery were gastrointestinal stromal tumor (5 patients) and tailgut or duplication cyst (4 patients). All procedures were completed endoscopically. The median distance from the anal verge was 7.3 cm (range, 5 to 10 cm), and the mean diameter of the tumors was 3 ± 1.1 cm. The one patient in whom the margins presented tumoral involvement underwent repeated TEM. No intraoperative complications were reported. The postoperative complication rate was 13.3%, and the mean length of hospital stay was 1.85 ± 1.77 days.

CONCLUSIONS

TEM for retrorectal and submucosal rectal lesions is feasible and safe. A remarkably low morbidity rate and limited surgical injury favor TEM in selected patients.

Local excision: is it an adequate substitute for radical resection in T1/T2 patients?

Local excision (LE) was historically developed to palliate patients with rectal adenocarcinoma who either are medically unfit or have adamantly refused to undergo transabdominal standard resection (SR) procedures. Over the years, the tradeoffs between the oncologic benefit and adverse functional sequelae associated with SR procedures have been increasingly recognized. In parallel, there has been growing interest in considering LE as an alternative to SR in select patients with early-stage disease. However, concerns regarding its oncologic adequacy remain. These concerns relate to the adequacy of tumor resection, the removal of mesorectal disease, the accuracy of preoperative selection, and the use of adjunctive treatment modalities. Evolving strategies that aim at improving the oncologic outcomes of LE for stage I T1/T2 rectal cancers include adoption of transanal endoscopic microsurgery and the addition of non-surgical modalities. Current evidence surrounding these approaches is examined to provide a basis for an informed discussion with patients. Key factors to be considered in formulating the treatment plan for an individual patient with T1/T2 rectal cancer are summarized.

Initial experience with transanal endoscopic microsurgery: the need for understanding the limitations

INTRODUCTION

Transanal endoscopic microsurgery is an alternative to transanal excision or radical surgery for benign and carefully selected malignant rectal tumors. Advantages over transanal excision include better visualization, access to more proximal lesions, higher likelihood of negative margins, and lower recurrence rates. Compared to radical resection, patients experience lower rates of morbidity and mortality but may have higher rates of local recurrence.

METHODS

A review of a prospectively maintained database of patients scheduled for transanal endoscopic microsurgery was performed.

RESULTS

Ninety-three patients underwent 96 procedures for 13 carcinoid tumors, 1 submucosal mass, 46 adenomas, 12 in situ adenocarcinomas, and 21 invasive adenocarcinomas. Of these cases, 81.2% was successfully completed. There were nine complications (11.5%). Final pathology demonstrated 33 in situ and invasive adenocarcinomas. The mean follow-up was 25.9 months. The four recurrences (12.1%) occurred in: one tubulovillous adenoma, two in situ carcinomas, and one T2 lesion.

CONCLUSIONS

Transanal endoscopic microsurgery is appropriate for benign lesions such as carcinoid tumors and adenomas and can also be curative in carefully selected patients with early-stage invasive rectal cancer. In cases of invasive adenocarcinoma, it should be reserved for low-risk cancers in patients who accept the possible increased risk of recurrence.

Transanal single port microsurgery (TSPM) as a modified technique of transanal endoscopic microsurgery (TEM)

BACKGROUND

Single port access (SPA) surgery is a new procedure for minimal invasive surgery using one multichannel port. The authors adapted this technique for transanal surgery as an improvement of the transanal endoscopic microsurgery (TEM).

METHODS

A total of 3 patients underwent SPA modified TEM using the SILS port (Covidien) under CO(2) insufflation. This port allows insertion of 2 laparoscopic instruments and a telescope.

RESULTS

The operation was completed successfully in all cases. The transanal placement of the SILS port was easy to perform; a prior dilatation of the anal sphincter was not necessary. There were no perioperative or postoperative complications as verified by postoperative observation, rectoscopy, and anal ultrasound.

CONCLUSIONS

Transanal single port microsurgery is a feasible and new technique for less invasive and more gentle transanal surgery. By using this new multichannel device TEM surgery was changed in a modified way while preserving the anal sphincter.

Transanal endoscopic operation: a new proposal

PURPOSE

The transanal procedure for rectal cancer surgery is one of the many techniques currently available. Different techniques for local excision of rectal tumors include: conventional transanal technique, posterior access surgery, therapeutic colonoscopy, transanal endoscopic surgery.

METHODS

The aim of the present study is to describe a new method of transanal endoscopic resection, transanal endoscopic operation (TEO), and performed with the aid of a surgical proctoscope especially designed for this purpose and report the results obtained in 32 patients submitted to the TEO and to compare these results with those obtained with other techniques currently available. The average proportions of recurrence, post-operation complications and posterior resections were analyzed by means of a metanalysis. Data on the distance and size of rectal lesions, the operative timing and hospitalization time were distributed in graphs according to authors and techniques.

RESULTS

The results were favorable and equivalent to those described in the literature.

CONCLUSIONS

The surgical proctoscope specially designed for this study is efficient and has a low cost; the TEO is easily performed with the aid of this equipment; the final results were favorable and similar to those obtained with other available techniques for endoscopic transanal intestinal resection, which are of high cost and less availability.

A new proctoscope for transanal endoscopic operations

Transanal access is one of many currently used procedures for rectal cancer treatment. The techniques used for local excision include conventional transanal excision, posterior access, therapeutic colonoscopy and transanal endoscopic approaches. The aim of the present study was to present a new surgical proctoscope for the endoscopic transanal excision of rectal lesions. A cylindrical proctoscope with a diameter of 4 cm was devised and built. The end inserted into the anus has a bevelled aspect and rounded borders, allowing correct exposure of the anal lesion. The rectoscope is fixed to the anal border with surgical thread through perforations in the external end. A base screw holds a fibre-light which illuminates the operative field. Part of the equipment is a guide which is positioned inside the rectoscope on insertion into the anus. In operations utilizing this proctoscope, 17 adenomas, 25 adenocarcinomas, 1 carcinoid and 1 endometrioma were excised. The diameter of the lesions varied from 1 to 6 cm. The range of procedures that are possible with this new proctoscope are similar to those achieved with conventional techniques which, however, require more expensive equipment. Hence, the present study demonstrates that this newly devised low-cost proctoscope is an efficient tool for the transanal endoscopic excision of rectal lesions.

Neoadjuvant chemoradiation and local excision for T2-3 rectal cancer

BACKGROUND

Local excision (LE) of T1 low-risk (G1-2/L0/V0) rectal cancer is an established approach with local recurrence (LR) rates of approximately 5%, whereas LE of > or = T2 high-risk tumors or inadequate resections (R1/RX/R < or = 1 mm) showed high recurrence rates. Because of the favorable results after neoadjuvant chemoradiotherapy (nCRT) and radical surgery of disease that completely responds (CR) with almost absent LR even of T3-4 tumors, an extension of the indication for LE is controversially discussed, and therefore, we assessed this therapeutic option.

METHODS

Including our own data, seven studies about LE after nCRT of cT2-3 tumors (n = 237) were analyzed after a PubMed search for cT categories, tumor height, nCRT regimens, schedule and technique of surgery, complications, freedom of stoma, response rates (ypT0-3), length of follow-up, LR, and metastases.

RESULTS

Subgroups that we formed (retrospective vs. prospective/retractor vs. transanal endoscopic microsurgery) showed differences in the distribution of cT categories. However, neither the studies we considered nor our own patients showed LR in CR (ypT0). In addition, patients with ypT1 tumor consistently showed low LR rates of 2% (range, 0%-6%), whereas in ypT2 findings, less favorable LR rates of 6% to 20% were observed, and disease that did not respond to therapy (ypT3) displayed LR rates in up to 42%.

CONCLUSIONS

Despite of a highly selected patient collective, an extended indication for LE of cT2-3 rectal cancer after nCRT may be considered. The strongest prognostic factors were a CR (ypT0) or responses on submucosa level (ypT1). These first results will have to be confirmed in a prospective trial with an appropriate sample size to ensure high statistical power.

Surgical management of rectal cancer

Rectal cancer affects more than 40,000 people in the United States annually. Despite recent advances in radiation and chemotherapy, surgical resection remains an integral part of curative therapy for this disease. Although rectal cancer is thought to be biologically similar to colon cancer, the anatomic complexity of the pelvis makes therapy for this disease considerably more complicated. Local recurrence is also a greater concern in rectal cancer than in colon cancer. The choice of surgical therapy depends on the location of the tumor, depth of rectal wall invasion, and clinical stage. Surgical options include local excision (transanal excision and transanal endoscopic microsurgery) and radical resection (low anterior resection, extended low anterior resection with coloanal anastomosis, abdominoperineal resection [APR], and pelvic exenteration). Technical advances such as transanal endoscopic microsurgery and laparoscopy also are changing the surgical approach to rectal tumors. Finally, chemotherapy and radiation are now frequently recommended in conjunction with surgical therapy. This article reviews the current surgical approach to treating patients with rectal cancer.

Rectal carcinoids

PURPOSE OF REVIEW

To provide an updated review of the diagnosis, management, and treatment of rectal carcinoid tumors, with special emphasis on minimally invasive surgical techniques to treat localized disease.

RECENT FINDINGS

Carcinoids are morphologically and biologically heterogeneous neuroendocrine tumors that have malignant potential, and are most commonly found in the gastrointestinal tract. The incidence of all carcinoids appears to be increasing, which may reflect improved diagnostic modalities. The rectum is the third most common location for gastrointestinal carcinoids. Recent data have suggested that rectal carcinoids are over-represented in Black and Asian populations. The survival rate for patients with rectal carcinoids is superior to that of carcinoids found elsewhere in the gastrointestinal tract. Tumor size in rectal carcinoids is predictive of metastasis and can reliably guide management. Review of recent literature demonstrates good evidence that localized rectal carcinoids are amenable to local resection.

SUMMARY

With widespread colorectal cancer screening, heightened awareness, and improved diagnostic modalities, the incidence of rectal carcinoids should continue to increase. There is evidence that convincingly demonstrates that patients with rectal carcinoids less than 2 cm in diameter, localized to the mucosa or submucosa, may be safely and effectively removed via minimally invasive resection.